15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2012 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef BASE_SUPPORTS_USER_DATA_H_ 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define BASE_SUPPORTS_USER_DATA_H_ 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <map> 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/base_export.h" 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/memory/linked_ptr.h" 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/memory/ref_counted.h" 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/threading/thread_checker.h" 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace base { 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This is a helper for classes that want to allow users to stash random data by 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// key. At destruction all the objects will be destructed. 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class BASE_EXPORT SupportsUserData { 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) SupportsUserData(); 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Derive from this class and add your own data members to associate extra 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // information with this object. Alternatively, add this as a public base 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // class to any class with a virtual destructor. 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) class BASE_EXPORT Data { 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual ~Data() {} 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }; 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The user data allows the clients to associate data with this object. 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Multiple user data values can be stored under different keys. 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // This object will TAKE OWNERSHIP of the given data pointer, and will 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // delete the object if it is changed or the object is destroyed. 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Data* GetUserData(const void* key) const; 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void SetUserData(const void* key, Data* data); 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void RemoveUserData(const void* key); 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // SupportsUserData is not thread-safe, and on debug build will assert it is 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // only used on one thread. Calling this method allows the caller to hand 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // the SupportsUserData instance across threads. Use only if you are taking 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // full control of the synchronization of that hand over. 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void DetachUserDataThread(); 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) protected: 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual ~SupportsUserData(); 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typedef std::map<const void*, linked_ptr<Data> > DataMap; 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Externally-defined data accessible by key. 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DataMap user_data_; 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Guards usage of |user_data_| 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ThreadChecker thread_checker_; 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(SupportsUserData); 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Adapter class that releases a refcounted object when the 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// SupportsUserData::Data object is deleted. 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <typename T> 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class UserDataAdapter : public base::SupportsUserData::Data { 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 644e180b6a0b4720a9b8e9e959a882386f690f08ffTorne (Richard Coles) static T* Get(SupportsUserData* supports_user_data, const void* key) { 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) UserDataAdapter* data = 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<UserDataAdapter*>(supports_user_data->GetUserData(key)); 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return data ? static_cast<T*>(data->object_.get()) : NULL; 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) UserDataAdapter(T* object) : object_(object) {} 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) T* release() { return object_.release(); } 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) scoped_refptr<T> object_; 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(UserDataAdapter); 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace base 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // BASE_SUPPORTS_USER_DATA_H_ 82